1. Field of the Invention
The present invention relates to an image forming apparatus such as an electrophotographic copier, printer or the like and, in particular, to a system and method for providing a simplified upgrade path for a color image forming apparatus.
2. Background Art
Electrophotographic imaging (or xerography) is a well known method of copying or otherwise printing documents. In general, electrophotographic imaging uses a charge-retentive, photosensitive surface (known as a photoreceptor), that is initially charged uniformly. The photoreceptor is then exposed to a light image representation of a desired image that discharges specific areas of the photoreceptor surface creating a latent image. Dry toner powder is applied to the latent image, forming a developed image. This developed image is then transferred from the photoreceptor to a substrate (e.g. paper, transparency, and the like) generally by the use of electrostatic attraction between the charged toner particles and oppositely charged ions sprayed on the substrate by a transfer charger.
This electrophotographic process can be used to produce color images by repeating the above-described process for each color of toner used. This approach is referred to a tone-on-tone (or xe2x80x9cimage-on-imagexe2x80x9d) color accumulation approach. In the general case of a tone-on-tone electrophotographic apparatus, the device includes a photoreceptor (belt or drum), a series of four print stations (e.g. yellow, magenta, cyan and black), a transfer charger, some means for placing the substrate (paper or otherwise) between the photoreceptor and transfer charger and some means for fixing the positive toner image on the substrate. The photoreceptor is supported and generally driven to rotate such that each part of the photoreceptor is brought into operable registration with the print stations and transfer charger.
Each of the four print station generally includes three components: a charger, a light exposure device and a developer. The operation and interaction of each print station is generally the same. The charger charges the image area of the photoreceptor uniformly. (The charger can be any device capable of setting up a uniform electric field on the order of 500 volts magnitude on the photoreceptor, such as an AC or DC corotron, scorotron, dicorotron, a discorotron, a pin scorotron.)
The light source (any coherent light source, such as a laser or light emitting diode xe2x80x9cLEDxe2x80x9d) selectively exposes the photoreceptor to a modulated light causing the photoreceptor charge to dissipate wherever light falls. By controlling the light beam and its scan path the latent image is created. The developer provides toner having a charge opposite to that of the photoreceptor. The developers used in tone-on-tone processes have no physical contact with the photoreceptor because such contact would disturb previously deposited toner.
The various toners which accumulate on the photoreceptor are transferred from the photoreceptor to substrate by operation of transfer charger. In particular, a substrate is placed between the photoreceptor and transfer charger by a drive means, the transfer charger sprays ions having a charge opposite to that of the tonerxe2x80x94on the back of the substrate to attract the toner onto the substrate. The resulting image is then fixed on to the substrate by way of a fuser unit or other fixing device and the substrate is fed into an output tray.
Unfortunately, these color capable electrophotographic systems tend to be expensive to produce because of the quantity and complexity of the components. As a result, these types of systems are only available to wealthier businesses that can afford the high cost. At present, attempts to solve this problem include new electrophotographic systems that only use one or two print stations to produce the color image at a lower cost. However, this approach is not a highly desirable solution because the speed of the processing increases when fewer print stations are utilized because the photoreceptor must then perform multiple passes for each color. Therefore, there is a need for an electrophotographic imaging system that is both quick and affordable.
Similarly, color capable electrophotographic systems have been more expensive and time consuming to repair than monochrome systems. The additional parts result in more frequent problems and require availability of greater replacement parts. In some cases, this leads to increase time before repair service is even available for a businesses. Consequently, there is a need for an electrophotographic imaging system that provides for quicker repair.
A number of technical advances are achieved in the art, by implementation of an imaging system including a plurality of developing stations for developing an image on a sheet, a releasably removable image receiving module having at least one exposing unit and an image receiving substrate and a support structure for receiving the releasably removable image receiving module. The releasably removable image receiving module is configured to engage the support structure of the system such that the image receiving substrate of the module can be disposed in an operative relationship with the developing stations when the removable module is engaged with the support structure.
This imaging system provides a method for upgrading, downgrading or modifying the imaging system that could be substantially performed by an end user.
This imaging system may be embodied in a monocolor or multicolor printer, copier, facsimile machine or other electrophotographic based apparatus.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.